Quick-cooking wheat and method of making same



Patented Sept. 22, 1953 QUICK-COOKING WHEAT AND METHOD OF MAKING SAME Charles R. Carman, Park Forest, and Jim E. Allison, Elmhurst, 111., assignors to Guardite Corporation, a corporation of Delaware No Drawing. Application June 12, 1953, Serial No. 361,422

Claims. 1

This invention relates to a pre-cooked cereal and a method of preparing the same and particularly to a pre-cooked wheat.

This application is a continuation-in-part of our co-pending application, Serial No. 190,664, filed October 1'7, 1950, now abandoned, which in turn was a continuation-in-part of our then copending application, Serial No. 161,744, filed May 12, 1950, now abandoned.

The pre-cooking of cereal is not a new art, but the problem of pre-cooking cereals, drying them, and then having them reconstitute rapidly in water, without loss of flavor, palatability, or granular identity has heretofore not been satisiactorily solved.

The formation of the present wheat product involves the following factors:

1. In order to procure a uniform wheat product, the moisture content of thematerial should be uniform as between the wheat grains and uniform throughout each grain. Depending upon the type of wheat employed, the moisture range will vary and the uniformity may be obtained as desired.

2. The wheat should be cooked by steam or otherwise under conditions which establish a proper moisture content and cause the starch to become uniformly gelatinized so as to bring the wheat to a sufiicient state of plasticity properly to expand. The conditions should be adjusted so that each grain should be cooked to substantially the same degree and in addition these conditions are preferably of such a nature that the non-condensable gases in the grains are removed therefrom. This latter condition may be established under vacuum conditions under which the contained moisture boils and washes out the noncondensable gases in the grains. During the cooking a bleed or purge line is maintained so that any non-condensable gases generated during the cooking or supplied with the cooking may be eliminated.

3. When the wheat is properly cooked and is at the proper moisture content, it is suddenly shot into a vacuum zone, causing expansion of the wheat. The conditions of the resultin explosion should be such as to cause cold setting of the wheat. The temperature is determined by the vacuum conditions into which the wheat is fired and the ability to maintain these conditions during the resulting explosion and concomitant expansion of the wheat. This means that with commercially practicable vacuum equipment, the expansion chamber should have a volume enormously greater than the cooking chamber. In

2 vacuum at the start of the expansion of the wheat is of the order of 0.1 to 0.2 inch of mercury absolute. In such apparatus the pressure may ride up somewhat during the explosion step. It is preferred to continue evacuation of the expansion chamber during the explosion and to maintain it at as low a pressure as is practicable. The temperature to which the wheat product is cooled is normally determined by the vacuum condition during the explosion step.

4. The starch is substantially completely gelatinized.

5. The time-temperature relationships are sufiiciently short and low respectively, that browning or scorching is avoided.

6. The wheat must not be so much cooked as to change the cell walls so as to render them impervious to steam, since otherwise they would rupture on expansion.

'7. The moisture content, and cooking time, temperature and pressure, and the vacuum into which the wheat is fired are selected to produce a wheat product which has a volume from 1 to 3 times the original wheat grains as determined by their cup weights. Put conversely, the specific gravity as determined by cup weights is from 28.5% to the specific gravity of the original wheat grains.

Removal of the non-condensable gases from the wheat, cooking, and vacuum expansion are preferably carried out in a puffer of the type disclosed in the Doyle Patent No. 2,627,221, issued February 3, 1953. In such an apparatus a steaming chamber is provided within which the wheat grains may be placed. This steaming chamber is connected by a triggered door to an expansion chamber. The expansion chamber is preferably kept at a low pressure, means being provided to maintain a low pressure during the expansion. The steaming chamber is provided with an evacuating means, steaming means, and usually with a purge or bleed line through which non-condensable gases can be eliminated as well as some condensed steam which develops during steammg.

The steps of removing the non-condensable gases from the Wheat grains in cooking may be carried out before introduction into the puiier, but convenience is best served by carrying out the operation in one device.

In accordance with the present; invention, hard winter wheat, finely ground in accordance with usual practice, was employed. Such a material, prior to precooking, is now available on the market under the name, Blue Cross Whole Wheat. Its cooking time is normally about ten minutes.

The material, prior to treatment, had a cup weight of approximately 117 grams.

The material Was processed in ten pound lots,

' It without any moistening or tempering operation. Tempering may be employed, but it has not been found to improve the material and, in some cases has a deleterious effect.

The wheat is placed in the steaming chamber, and evacuation carried out to approximately 0.1 to 0.2 inch of mercury absolute for about two minutes, the wheat being at a temperature of not less than about 40 F. to remove the non-condensable gases from the wheat grains. Steam is then introduced to the steaming chamber accompanied by continued purging to cook the grains and remove any condensate and noncondensable gases. The product is cooked sufiiciently to gelatinize the starch, inactivate enzymes and supply sufiicient plasticity for vacuum expanding. The amount of cooking required will vary considerably with the characteristics of the Wheat grain, but may readily be determined by a preliminary test for any particular lot. The preferred cooking cycle is to introduce steam to reach 50 pounds per square inch gauge in 20 to 25 seconds, after which the material is expanded by opening the triggered door to the expansion chamber which is at a pressure of about 0.2 inch of mercury absolute. Normally, the pressure in the expansion chamber is not permitted to rise above about two inches of mercury absolute until cold setting of the vacuum expanded wheat grains occurs. In some instances We have operated successfully with the pressure in the expansion chamber following explosion riding up as high as 3 /2 to '7 inches of mercury absolute as measured on a standard mercury manometer, but in most instances the pressure was reduced below two inches of mercury absolute within a few minutes, and before reimposition of atmospheric pressure.

In one specific example, the steaming cycle was fifty pounds per square inch gauge of steam pressure reached in twenty-three seconds. In another, it was seventy-five pounds per square inch gauge of steam pressure reached in twentysix seconds. In another, it was thirty-five pounds per square inch gauge of steam pressure reached in twenty-two seconds. In another it was twentyfive pounds per square inch gauge steam pressure reached in twenty-two seconds.

After expanding, the product was dried by the introduction of superheated steam at about one inch of mercury absolute into the expansion chamber and continuing this operation for ten minutes. That is, steam was continuously admitted while the evacuating apparatus was operated so that the pressure did not rise above one inch of mercury absolute. It is preferred to have a moisture content of approximately in the product before further processing.

The expanded and dried whole wheat was then put through corrugated rolls. These corrugations cut the grains up to some extent, broke up clusters, and removed some loose starch from the grains.

The vacuum expanded wheat product has a volume from 1 to 3 times the original wheat grains. Put conversely, the specific gravity as determined by cup weight is from 28.5% to 60% of the specific gravity of the original wheat grains. It is granular in appearance, the grains being of a mixed brown and white color and substantially the shape of the original grains. It is capable of remarkably fast Water absorption and can be cooked in approximately thirty seconds, as compared to ten minutes required for the original material.

In cooking, one cup of the processed wheat is slowly stirred into one and one-quarter cups of boiling water containing a quarter teaspoon of salt. The boiling is carried out for thirty seconds, after which the wheat is ready for serving.

The cooking operation increases the moisture content of the grain approximately 1% for each twenty to twenty-five degrees F. increase in temperature. This increase is lost on vacuum expanding, and the loss of water, plus the sudden cooling is believed to cause setting of the plasticity of the walls so that they will not collapse upon subsequent increase in pressure.

The starchy portions of the processed wheat are translucent. The surfaces have a somewhat vitreous appearance. The bundle of starch cells somewhat resembles a snowball.

The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

We claim:

1. The method of treating wheat which comprises: substantially removing the air from the wheat and substituting an atmosphere of steam under pressure; adding steam thereto at increased pressure and temperature to raise the moisture content thereof and cook the wheat; then instantaneously reducing thepressure from at least about 25 pounds per square inch gauge to Well below atmospheric pressure to cause an explosion resulting in expansion of the wheat; and maintaining a reduced pressure sufiicient to cold set the expanded wheat material during the explosion and until cold setting of the wheat occurs, the pressure at the inception of the explosion and the extent of pressure reduction being correlated to produce an expanded product hav ing a specific gravity between about 28.5% and 60% of the original ground wheat.

2. The method as set forth in claim 1, in which the steam operation is carried on to reach a pressure of from about 25 pounds to 75 pounds per square inch gauge.

3. The method as set forth in claim 1, in which the instantaneous pressure reduction is to 2 inches of mercury absolute or less.

4. The method as set forth in claim 1, in which the final moisture content of the expanded wheat product prior to reimposition of atmosphere pressure is from 10% to 15%.

5. A cold set vacuum expanded quick-cooking wheat product produced by the process of claim 1.

CHARLES R. CAR/MAN. JIM E. ALLISON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,933,158 Bohn et al Oct. 31, 1933 2,261,456 Warren 1 Nov. 4, 1941 2,287,737 Huzenlaub June 23, 1942 2,358,251 l-I'uzenlaub Sept. 12, 1944 2,552,291 Rupp May 8, 1951 FOREIGN PATENTS Number Country Date 19,195 Great Britain of 1895 18,949 Great Britain of 1912 514,102 Great Britain Oct. 31, 1939 

1. THE METHOD OF TREATING WHEAT WHICH COMPRISES: SUBSTANTIALLY REMOVING THE AIR FROM THE WHEAT AND SUBSTITUTING AN ATMOSPHERE OF STEAM UNDER PRESSURE; ADDING STEAM THERETO AT INCREASED PRESSURE AND TEMPERATURE TO RAISE THE MOISTURE CONTENT THEREOF AND COOK THE WHEAT; THEN INSTANTANEOUSLY REDUCING THE PRESSURE FROM AT LEAST 25 POUNDS PER SQUARE INCH GAUGE TO WELL BELOW ATMOSPHERIC PRESSURE TO CAUSE AN EXPLOSION RESULTING IN EXPANSION OF THE WHEAT; AND MAINTAINING A REDUCED PRESSURE SUFFICIENT TO COLD SET THE EXPANDED WHEAT MATERIAL DURING THE EXPLOSION AND UNTIL COLD SETTING OF THE WHEAT OCCURS, THE PRESSURE AT THE INCEPTION OF THE EXPLOSION AND THE EXTENT OF PRESSURE REDUCTION BEING CORRELATED TO PRODUCE AN EXPANDED PRODUCT HAVING A SPECIFIC GRAVITY BETWEEN ABOUT 28.5% AND 60% OF THE ORIGINAL GROUND WHEAT. 